From 84512c0e7f4441f060026f4fd9ddb7611fc10de4 Mon Sep 17 00:00:00 2001 From: Diego Russo Date: Wed, 3 Jul 2024 14:22:21 +0100 Subject: GH-119726: Emit AArch64 trampolines out-of-line (GH-121280) --- .../2024-06-28-18-34-49.gh-issue-119726.Fjv_Ab.rst | 2 ++ Tools/jit/_stencils.py | 14 ++++++-------- 2 files changed, 8 insertions(+), 8 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2024-06-28-18-34-49.gh-issue-119726.Fjv_Ab.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-06-28-18-34-49.gh-issue-119726.Fjv_Ab.rst b/Misc/NEWS.d/next/Core and Builtins/2024-06-28-18-34-49.gh-issue-119726.Fjv_Ab.rst new file mode 100644 index 0000000..cf5d614 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-06-28-18-34-49.gh-issue-119726.Fjv_Ab.rst @@ -0,0 +1,2 @@ +Optimize code layout for calls to C functions from the JIT on AArch64. +Patch by Diego Russo. diff --git a/Tools/jit/_stencils.py b/Tools/jit/_stencils.py index 68eb1d1..1c6a9ed 100644 --- a/Tools/jit/_stencils.py +++ b/Tools/jit/_stencils.py @@ -184,7 +184,7 @@ class Stencil: self.disassembly.append(f"{offset:x}: {' '.join(['00'] * padding)}") self.body.extend([0] * padding) - def emit_aarch64_trampoline(self, hole: Hole, alignment: int) -> None: + def emit_aarch64_trampoline(self, hole: Hole, alignment: int) -> Hole: """Even with the large code model, AArch64 Linux insists on 28-bit jumps.""" assert hole.symbol is not None reuse_trampoline = hole.symbol in self.trampolines @@ -194,14 +194,10 @@ class Stencil: else: self.pad(alignment) base = len(self.body) - where = slice(hole.offset, hole.offset + 4) - instruction = int.from_bytes(self.body[where], sys.byteorder) - instruction &= 0xFC000000 - instruction |= ((base - hole.offset) >> 2) & 0x03FFFFFF - self.body[where] = instruction.to_bytes(4, sys.byteorder) + new_hole = hole.replace(addend=base, symbol=None, value=HoleValue.DATA) if reuse_trampoline: - return + return new_hole self.disassembly += [ f"{base + 4 * 0:x}: 58000048 ldr x8, 8", @@ -219,6 +215,7 @@ class Stencil: self.body.extend(code) self.holes.append(hole.replace(offset=base + 8, kind="R_AARCH64_ABS64")) self.trampolines[hole.symbol] = base + return new_hole def remove_jump(self, *, alignment: int = 1) -> None: """Remove a zero-length continuation jump, if it exists.""" @@ -294,8 +291,9 @@ class StencilGroup: in {"R_AARCH64_CALL26", "R_AARCH64_JUMP26", "ARM64_RELOC_BRANCH26"} and hole.value is HoleValue.ZERO ): - self.code.emit_aarch64_trampoline(hole, alignment) + new_hole = self.data.emit_aarch64_trampoline(hole, alignment) self.code.holes.remove(hole) + self.code.holes.append(new_hole) self.code.remove_jump(alignment=alignment) self.code.pad(alignment) self.data.pad(8) -- cgit v0.12